I like the Mines of Gal Dur, but I thought of an idea to make them better. Instead of granting three iron resources, why not have the city that builds the Mines of Gal Dur "discover" three iron resources within its fat cross. This would dramatically increase the production of the city, which seems to be the intent of the wonder. The additional Engineer slots and other benefits seem alright. Maybe it could also increase the chance of discovering mineral resources, like an additional Earth Mana or something.